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| author | Tobin Feldman-Fitzthum <tobin@linux.ibm.com> | 2024-04-29 20:07:19 +0000 |
|---|---|---|
| committer | mergify[bot] <37929162+mergify[bot]@users.noreply.github.com> | 2024-06-25 15:27:42 +0000 |
| commit | 10b4bb8d6d0c515ed9663691aea3684be8f7b0fc (patch) | |
| tree | 257b4d0f0f94c467b75401852a700406aa814a62 /OvmfPkg/AmdSev | |
| parent | 56059941ec8c2f4d8fb126227b1154f8a869ac2b (diff) | |
| download | edk2-10b4bb8d6d0c515ed9663691aea3684be8f7b0fc.tar.gz edk2-10b4bb8d6d0c515ed9663691aea3684be8f7b0fc.tar.bz2 edk2-10b4bb8d6d0c515ed9663691aea3684be8f7b0fc.zip | |
AmdSev: Halt on failed blob allocation
A malicious host may be able to undermine the fw_cfg
interface such that loading a blob fails.
In this case rather than continuing to the next boot
option, the blob verifier should halt.
For non-confidential guests, the error should be non-fatal.
Signed-off-by: Tobin Feldman-Fitzthum <tobin@linux.ibm.com>
Diffstat (limited to 'OvmfPkg/AmdSev')
| -rw-r--r-- | OvmfPkg/AmdSev/BlobVerifierLibSevHashes/BlobVerifierSevHashes.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/OvmfPkg/AmdSev/BlobVerifierLibSevHashes/BlobVerifierSevHashes.c b/OvmfPkg/AmdSev/BlobVerifierLibSevHashes/BlobVerifierSevHashes.c index 37c38e9e98..bc2d5daadc 100644 --- a/OvmfPkg/AmdSev/BlobVerifierLibSevHashes/BlobVerifierSevHashes.c +++ b/OvmfPkg/AmdSev/BlobVerifierLibSevHashes/BlobVerifierSevHashes.c @@ -83,6 +83,7 @@ FindBlobEntryGuid ( @param[in] BlobName The name of the blob
@param[in] Buf The data of the blob
@param[in] BufSize The size of the blob in bytes
+ @param[in] FetchStatus The status of the previous blob fetch
@retval EFI_SUCCESS The blob was verified successfully or was not
found in the hash table.
@@ -94,13 +95,27 @@ EFIAPI VerifyBlob (
IN CONST CHAR16 *BlobName,
IN CONST VOID *Buf,
- IN UINT32 BufSize
+ IN UINT32 BufSize,
+ IN EFI_STATUS FetchStatus
)
{
CONST GUID *Guid;
INT32 Remaining;
HASH_TABLE *Entry;
+ // Enter a dead loop if the fetching of this blob
+ // failed. This prevents a malicious host from
+ // circumventing the following checks.
+ if (EFI_ERROR (FetchStatus)) {
+ DEBUG ((
+ DEBUG_ERROR,
+ "%a: Fetching blob failed.\n",
+ __func__
+ ));
+
+ CpuDeadLoop ();
+ }
+
if ((mHashesTable == NULL) || (mHashesTableSize == 0)) {
DEBUG ((
DEBUG_WARN,
|